Materials definitions Flashcards
Stress
Force per unit cross sectional area.
Strain
Extension per unit length.
Young modulus
Ratio of tensile stress to tensile strain (stress/strain) (as long as the limit of proportionality has not been reached).
Limit of proportionality
The limit beyond which, when a wire or a spring is stretched, its extension is no longer proportional to the force that stretches it.
Elastic limit
Point beyond which a wire does not return to its original length when the load is removed.
Yield point
The point at which stress in a wire suddenly drops when the wire is subjected to increasing strain.
Ultimate Tensile Stress (UTS)
The maximum tensile stress a material can withstand.
Plastic Deformation
Deformation of a solid beyond its elastic limit – the object will not return to its original length (size and shape) when the load is removed.
Elastic Deformation
The object will return to its original length (size and shape) when the load is removed.
Hooke’s Law
The force needed to stretch a spring is directly proportional to the extension of the spring from its natural length, up until the limit of proportionality.
Tensile
This type of deformation is one that stretches the object
Compressive
This type of deformation is one that compresses the object
Brittle
Snaps/breaks without noticeable deformation
Ductile
Can undergo large plastic deformation without breaking (can be drawn into long thin wires).
Density
Mass per unit volume
